The Studies On Synthesis And Characterization Of Schiff-base Based On1,8-naphthyridine And Rhodamine B As Metal Ions Fluorescent Probes

Due to the unique physical properties such as light,electricity,magnetism,anti-tumor,oxidation resistance and good coordination ability,Schiff-base compounds are widely used in the fields of medicine,catalysis,optical materials and chemical sensors.In this paper,three Schiff-base compounds have been designed and synthesized based on 1,8-naphthyridine derivative and rhodamine B derivative.Additionally,their fluorescence sensing properties have been studied.The details are as follows:In the first chapter,we make a brief introduction to the Schiff-base compounds,rhodamine fluorescent dyes,1,8-naphthyridine compounds and naphthalimide compounds.Furthermore,the composition and recognition mechanisms of fluorescent probes have been summarized.Finally,we have presented the research progress of Al³⁺and M³⁺fluorescent probes.In the second chapter,we have designed and synthesized a Al³⁺fluorescent probe L¹ based on1,8-naphthyridine.The probe can detect Al³⁺with high selectivity and high sensitivity in methanol,while the other common metal ions would not have a significant impact on the detection of Al³⁺.L¹ alone exhibited weak fluorescence emission at 414 nm.Upon addition of Al³⁺to the L¹methanol solution,a new complex was formed due to the coordination process between L¹ and Al³⁺.Thus,the PET process was restrained and the fluorescence emission intensity at 414 nm was enhanced remarkably.In the third chapter,we have designed and synthesized a M³⁺fluorescent probe L² based on rhodamine B.The probe had high selectivity towards M³⁺in methanol,while the other common monovalent and divalent cations would not influence the detection of M³⁺.L² alone did not exhibited any fluorescent emission and the solution of L² in methanol was colorless.Upon addition of M³⁺,the complexation between L² and M³⁺induced the formation of ring opening of the rhodamine B spirolactam.Thus,the methanol solution of L² changed from colorless to light pink accompanied with emitting strong fluorescence.This significant color change allows L² to detect M³⁺through the naked eye without resorting to additional instrumental analysis.In the fourth chapter,we also have designed and synthesized a rhodamine B-derived Schiff-base fluorescent probe L³ based on the second work.The probe also had high selectivity towards M³⁺in methanol,while the other common monovalent and divalent cations would not have a significant impact on the detecting of M³⁺.Upon addition of M³⁺,the solution of L³ in methanol changed from colorless to pink along with emitting strong fluorescence based on the similar recognition mechanism.Furthermore,L³ was successfully used in the convenient application research and the design of molecular logic gates due to the significant color change and good reversibility.In the last chapter,we have analyzed and summarized the finished work and made plans for the next research work.